Laptop won't connect to wireless network on Windows 7: Please Help!

Hi,

I am having trouble connecting my girlfriends laptop to the internet using her Windows 7 laptop via a Dlink router with Virgin Media. The laptop previously had Windows Vista installed but I recently upgraded it to Windows 7. For about 2 weeks the laptop connected to the wireless router fine, but stopped working about 4 days ago for some unknown reason out of the blue.

We have tried various methods to fix it, including disabling the wireless network adapter and enabling it again, we have tried updating the driver for the adapter but we get a message saying that the driver currently installed is the latest driver. It also won't let me roll back to the previous driver as that option is faded out in the properties box.

I have took her laptop to my house today to try and connect it to my router (which is also with Virgin and is working fine on my computers at my house) and the laptop won't let me connect to the network and it keeps saying there are no network connections available. I understand that usually it displays a list of connections you can log on to, but the laptop is not finding any connections at all.

On Thursday we attempted to connect to the internet by plugging in the blue wire that came with the router and that works fine. It's just it will not connect wirelessly. What really baffles us with this problem is that it worked fine for a couple of weeks then suddenly stopped working. Could it be an update that was installed that has caused the problem perhaps?

I have also tried using System Restore but that hasn't fixed the problem either.

The wireless adapter is called: Atheros AR5005G Wirelss Network Adapter.

Please help as my girlfriend needs her Facebook fix and is very close to throwing her laptop out of the window

given that your wireless adapter is switched on and enabled in windows and in bios and ...at any time after this point you can stop if the wireless starts working again...

Disable any firewalls or antivirus apps that are installed.
Make sure you have the correct passkey for the network
Delete all wireless network properties from the manage wireless networks page and reenter your wep or wpa password if you have one.
Use windows to manage wireless network connections.
Uninstall any third party "wireless managers"
Reinstall windows
I'm sure others here can think of a few things that It haven't, but if you get to this point and it's still not working, it's possible there's a hardware failure